1. Field of the Invention
The present invention relates generally to apparatus and methods for manufacturing structural units, such as concrete blocks, brick, clay-based material, pavers, segmental retaining walls (SRWs), etc., from a mold and the structural units manufactured using these apparatus and methods and, in particular, to an insert apparatus for use in connection with a mold for manufacturing a structural unit, a method of manufacturing a structural unit having an engagement portion applied on a side or sides of the unit, a method of retrofitting an existing mold for manufacturing a structural unit having such engagement portions, and to a structural unit made using these apparatuses and methods.
2. Description of Related Art
In the field of manufacturing structural units, such as concrete, concrete blocks, pavers, bricks, SRWs and the like, a mold is required. In operation, a conveyor or similar transport mechanism moves a pallet or plate underneath the mold, which typically includes an open top, open bottom and multiple inner cavities for forming the concrete unit or structural unit. After the pallet or plate is moved into engagement with the underside of the mold, a fill drawer moves over the open top of the mold and places material, such as concrete or cement, into the inner cavity portion of the mold. Next, a machine head or plunger compresses the material, thereby providing additional compaction of the concrete material in the mold. Typically, the mold is vibrated while the concrete material is being placed or injected therein to provide better settling and uniformity.
After the concrete material is molded or shaped within the inner cavity of the mold, the pallet or plate moves down in a vertical manner away from the bottom of the mold and the compacted, consolidated and condensed concrete units also move down with the pallet. Typically, the concrete units are further cured, such as by natural curing, or by some other catalytic means. In this manner, a structural unit is manufactured.
Structural units, such as concrete blocks, cinder blocks and the like are used extensively in construction situations, as well as consumer applications. For example, a consumer may now wish to build his or her own retaining wall on their property. Therefore, a need has arisen for structural units that are more easily transported and manipulated in these fields and applications. In order to manufacture such specialized units, typically the mold must be modified to apply an engagement portion on a surface of the unit. There are different processes for accomplishing modified surfaces for structural units.
One drawback to applying a specific engagement portion or dimensioned projection or recess on a structural unit is the limitation of how a concrete unit is manufactured by the mold. As discussed above, the bottom of the plate moves to bound the mold and allow concrete material to be placed therein, and when this material is consolidated/compacted/condensed (CCC), the pallet or plate moves away from the bottom of the mold in a vertical direction. Therefore, any design that is placed upon a vertical surface of the concrete unit would be removed or otherwise distorted as the concrete unit drops down and slides through the mold via the pallet. While this does not pose an insurmountable problem when producing units with a roughened surface or similar pattern (since the design is not specific), systems and processes have been developed for applying these types of surfaces to a structural unit. For example, see U.S. Pat. No. 6,464,199 to Johnson; U.S. Pat. No. 6,209,848 to Bolles et al.; U.S. Pat. No. 6,138,983 to Sievert; U.S. Pat. No. 6,113,379 to LaCroix et al.; U.S. Pat. No. 5,217,630 to Sayles; and U.S. Pat. No. 5,879,603 to Sievert. See also Patent Application Publication No. U.S. 2001/0007380 to LaCroix et al. However, such processes and molds are deficient in that only a roughened or textured surface can be applied to the vertical face of the unit. Therefore, such systems and processes are not capable of producing a specified engagement portion or design, which could not be removed or distorted as the concrete unit is discharged from the mold.
Other processes have been developed for placing decorative surfaces, designs and indicia on a vertical face of the concrete unit. For example, see U.S. Pat. No. 5,817,249 to Forlini; U.S. Pat. No. 2,532,049 to Wittke; U.S. Pat. No. 1,693,693 to Dexter; and U.S. Pat. No. 1,635,093 to McPherson et al. However, these molds and processes are quite complicated. The mold must be specifically designed to create the design or indicia and typically a wall of the mold must be pressed and turned in towards the concrete material and then removed prior to dropping the unit from the mold. In addition, such intricate molds and machines are expensive and labor intensive, since multiple parts and walls and other mechanisms must be utilized to apply the indicia, remove the design portion and allow the block to be removed from the mold. Further, such molds and processes may not be well suited for the mass production of structural units.
There also remains a need for a structural unit that is easily manipulated and transported in construction, commercial and consumer situations. For example, it would be beneficial to provide some manner of grasping or otherwise holding a structural unit, which, as discussed above, is often very heavy. Therefore, while concrete or cinder blocks have a hollow core and may be grasped by these inner walls and moved about a construction site, the design of these prior art blocks makes them quite awkward to move and easily hold. Therefore, a need has arisen for a structural unit that a user can grasp and easily move around a particular site.